Electrical relay



H. O. HOLTE ELECTRICAL RELAY Feb. 21, 1923.

Original Filed Sept. 9, 1924 Fig. l.

Fig. 5.

INVENTO R I Patented Feb. 21, 1928.

UNITED STATES 1,660,197 PATENT OFFICE.

HAROLD O. HOLTE, DECEASED, LATE F PITTSBURGH, PENNSYLVANLA, BY HALVORf HOLTE, ADMINISTRATOR, OF CROOKSTON, MINNESOTA; HAROLD O. HOLTE AS- SIGNOR TO THE UNION SWITCH 8c SIGNAL COMPANY, OF SWISSVALE, PENNSYL- VANIA, A CORPORATION PENNSYLVANIA.

ELECTRICAL EELAY.

Original application filed September 9, 1924, Serial No. 736,683. Divided and this application filed May 28, 1926. Serial No. 112,283.

The invention relates to electrical relays, and particularly to relays of the type comprising a movable member arranged to be vibrated when alternating currents are sup- 6 plied to the relay.

One object of the present invention is the provision of a relay requiring for its operation the supply of two alternating currents of different frequencies and in which the movable member is responsive to the joint action of such currents.

The present case is a division of a copending application, Serial No. 7 36,683, filed Sept. 9, 1924, bythe said Harold O. Holte,

(now Patent No. 1,590,825, June 29, 1926) for railway traffic controlling apparatus.

Two forms of relays embodying the invention will be described, and the novel features thereof will then be pointed out in claims. I

In the accompanying drawings, Fig. 1 is a view, partly diagrammatic, showing one form of relay embodying. the invention. Fig. 2 is a sectional view showing another form of relay also embodying the invention. Fig. 3 is a view showing, in side elevation the relay illustrated in Fig. 2. Fig. 4 is an end 'viewof the rotor member-24 of the relay shown in Figs. 2 and 3.

Similar reference characters refer to similar parts in each of the several views.

Referring first to Fig. 1, the relay, designated in general by the reference character L, comprises a core-7 of magnetizable lilaterial, preferably'U-shaped as shown in the drawing, and a fixed member 9 also of magnetizable material located in the air gap 10' between the legs of the core 7. A winding 5 is located between the member 9 and 40 the legs of core 7 and this winding is mounted to oscillate about an axis which is perpendicular to the plane of the drawing. Mechanically attached to the winding 5 but electrically insulated therefrom is a contact member 8 which co-operates with a fixed contact member 8 for the control of any suitable apparatus not shown in the drawing. The core 7 \of the relay is provided with a winding 6 which is supplied with alternating current of one frequency from a suitable source such as'an alternator G. Winding 5 is at times supplied with alter- .natingcurrent of a second frequency from a suitable source such as the secondary 18 of a transformer H having its primary19 supplied with current from a second alternator K over a circuit controller 12. This forces are proportional to the strengths of.

the currents supplied to the relay windings and by making the current in winding 6 large, the relay can be made sensitive to very small currents in winding 5. i

If the winding 5 and the contact member 8, comprising the moving'element of the relay, are mechanically tuned to one of the vibromotive forces acting upon the element,

the response of the element will be considerable. Since, with a given vibromotive force, thedisplacement of the moving element is inversely proportional to the frequency, it is preferable to mechanically tune the moving element, by suitable means such as a slidable weight 11, to the difference of the two impressed frequencies.

When circuit controller 12 is open the moving element of the relay is at rest, and contact 88 is open. When the circuit controller is closed, however, the moving element of the relay'vibrates at the difference frequency of'the currents supplied to the relay andcontact 8---8 is periodically closed, the eriodicity of the operation of this contact eing the same as the frequency to which the moving element is mechanically tuned.

The contact 8-8 may be used to control the train carried apparatus of a railway traflic controlling system. In such a system the rimary 19 of the transformer H may be the rails of the track occupied by the 18 in inductive relation with the track rails.

Relays embodying the invention are particularly'suitable'for use in'systems of this train which carries the secondary winding 1 type because they are highly selective as to frequency. That'is to say, if the frequency of the current supplied to winding 5 varies by a small amount from the frequency upon which the relay is intended to operate, the frequency of the vibromotive forces acting upon the moving element of the relay is varied by a much larger proportion so that there is little or no danger of the relay being operated from the trackway by a stray current' of different frequency from that to which the apparatus is adjusted to respond.

Referring now to Figs. 2, 3 and 4, the vibration relay L here illustrated is of the induction motor type, comprising a stator 20, preferably of laminated iron, provided with four pole pieces 21, 21*, 22, and 22. More polepieces can be provided, and may be desirable. Pole pieces 21 and 21 are provided with a winding 5, whereas pole pieces 22 and 22 are provided with a winding 6, which windings maybe supplied with currents of different frequencies in the manner shown in Fig.1. Currents in windings 5 and 6 act on a rotor 24, which, as here shown, is of the shell type and is mounted for rotational vibration on two torsion strips 25 and 25, which strips are in turn supported in frameworks 26 and 26 attached to the stator member 20. Preferably a stationary iron core 23 is located inside of the rotor 24.

When alternating current-s of different frequencies are supplied to the two windings 5 and 6, they produce a torque on the rotor 24, which torque undergoes a cyclic variation in direction at the difference between the frequencies of the two impressed currents. If the rotor 24 is mechanically tuned to this difference frequency it will oscillate. rotor may be employed to operate a circuit controller in any desired manner, this cirvantages of light weight moving parts and low air friction losses. In any event, a relay wlth no moving iron is preferable, be-

cause it will not respond to the frequency.

of the current supplied to either winding of the relay no matter how strong these currents may be, but only to the difference of these frequencies to which the moving element is tuned mechanically.

Although only two forms of relay embodying the invention have been shown and described herein, it is understood that various changes and modifications may be made The therein within the scope of the appended claims without departing from the spirit and scope of the invention.

Having thus described the invention, what forces due to the joint action of said two currents and which is mechanically tuned to the frequency of one of said vibromotive forces.

2. A relay comprising means for creating two alternating magnetic fluxes of different frequencies, and a movable member subjected to-the resultant fluxes due to the joint action of said fluxes and tuned to mechanical resonance at the frequency of one of said resultant fluxes.

3. A relay comprising a movable member, and means for subjecting said member to the joint action of two vibromotive forces of different frequencies, said member being tuned to mechanical resonance at'the frequency of one of the resultant vibromotive forces acting thereupon.

4. A relay comprising means for creating two periodic fluxes of different frequencies, and a movable member subjected to the resultant fluxes due to the joint action of said two fluxes and tuned to mechanical resonance at a frequency equal to the difference member subjected to vibromotive forces due I to said currents and tuned mechanically to the difference between the frequencies of said currents.

7. A relay comprising a movable member, torsion strips for supporting said member, and means for subjecting said member to vibromotive forces of different frequencies simultaneously, said member being mechanically tuned to the difference between the frequencies of said vibromotive forces.

8. A relay comprising a stator having two windings, and a rotor whereby when currents of different frequencies are supplied to said two windings the torque acting on said rotor undergoes a cyclic variationin direction at the frequency of the diflerence between the frequencies of said currents, said rotor being mechanically tuned for rotational vibration at said difference frequency.

9. A relay comprising a conducting drum mounted for rotational vibration, means for subjecting said drum to twq alternating fluxes of different frequencies, said drum being mechanically tuned to the difference between the frequencies of said fluxes.

10. A relay comprising a stator provided with a winding supplied with periodic current of one frequency, a second winding supplied with periodic current of a different frequency, and a movable member subjected to the vibromotive forces due to the joint action of said currentsand tuned mechanically to resonance at the frequency of one of said vibromotive forces.

11 A relay comprising a stator provided with a winding supplied with periodic cur-. rent of one frequency, a movable member carrying a windingsupplied with periodic current of a difierent frequency and subjected to the influence of the torque due to the joint action of said currents and mechanically tuned to resonance at the difference between the frequency of said currents.

12. A relay comprising a U-shaped magnetizable core having an air gap between the extremities of its legs, a winding on said core supplied with alternating current of one frequency, a movable winding located in said air gap and supplied with alternating current of a different frequency, and a member attached to said movable winding and tuned to mechanical resonance at the difference between the frequencies of said currents.

-In testimony whereof I aflixmy signature.

. HALVOR HOLTE,

Administrator of H Mold 0. H olte, Deceased. 

